Voltage regulator



July 13, 1937.

C. W. HANSELL VOLTAGE REGULATOR Filed Feb. 8, 1934 Patented July 13,1937 PATENT OFFICE s z ,osasm VOLTAGE REGULATOR Clarence W. Hansell,Rocky Point, N. Y., asignar to Radio Corporation of America, a eo ofDelaware Y Appu'aaon February s, 1934, semi No. '110,235

s claims. l (o1. 1714-229) in which the same is carried out will bebetter A new type of resistance material has been recently developed inthe electrical arts. This material is permanent and has 'the property ofrapidly decreasing its electrical resistance when the voltage across itis increased. The characteristic of this resistance is non-linear. `Thatis to say, the current flow through the resistance in creases at a ratefaster than linear with respect to the increases of applied voltagewhich causes such current change. Although the relation between thechanges in current ilow and changes in applied voltage is not linear,said changes are continuous over the elective range of the resistancematerial which range is considerable. The

are described in the General Electric Review, February, 1930, vol. 33,No. 2, page 92, and has been called Thyrite, are such that doubling thevoltage upon it will decrease its resistance to less Vthan lone-sixth ofits initial value. The resistance of this 'material is relatively high,and the material is well adapted to high voltages and small Vcurrentrequirements such as for example anode circuits of thermionic tubes.

Cuprous oxide rectiflers, photo cells, lcesium oxide photo'cells,rectiers and similar devices have this non-linear characteristic ofdecreasing resistance when the Aapplied voltage is increased. Thesedevices, however, are well adapted to low voltage and heavy currentcircuit requirements.

In my invention this property of these .devices and material is made useof to regulate the voltage applied to any load as, for example, theheating elements of radio tubes `or the anodes or any other electrodesof said tubes. The decrease in the cell or resistance or rectierv whichoccurs with an increase of applied voltage causes a change in thecurrent flow therethrough which may be used to prevent the change ofvoltage causing said change in 'current vflow and consequently thechange of voltage in or across the useful load circuit. f,

My novel invention also contemplates the use of a resistance,` thecharacter of which is such that theresistance thereof increases rapidlywith the-increase of current flowing therethrough. .The use of thisresistance element properly placed in the circuit with the resistanceelement described above greatly increases the eifectiveness oi' the`voltage regulation.

Th novel features Oi' my invention have been pointed out withparticularity in the claims appended hereto. y

The nature of my invention and the manner characteristics of thisresistance material, which.v

- trol.

understood from the following description thereof and therefrom whenread in connection with the attached drawing in which Figures 1 to 3-in` clusive show circuits arranged in accordance with my presentinvention including a resistance, the current ilow through which isnon-linear with respect to the applied voltage, for applying constantpotentials from a direct current source which may vary to a loadcircuit; while Figure 4 is a curve indicating the relation between theapplied voltage and the current.

Figure 1 shows one of the simplest possible methods or and circuits forregulating voltages in accordance with my invention. This regulator issuitable for use either with direct current or alternating currentsources. In 1 a resistance R1V is connected between the source ofvariable voltage and the load or constant voltage output. A resistanceRv of suitable dimensions in which the current ow increasesnon-linearwith respect to the applied voltage, is connected across the leads I and2 as shown. As the potential from the source connected to the terminals3, 4 increases the current through the resistance Rv increases at afaster rate than the voltage and causes a variation in the voltage dropin the resistance Rv which counteracts the increase in voltage from thesource to insure a more constant voltage output at 5 and 6 which may beapplied to any load. 'Ihe regulation described above will be improved ifthe series resistance R1 is made of a-tungsten lament such as a lamp, orof any Vother material the resistance of which increases rapidly withincreasing current. Of course, where power consumption is of greatimportance the series resistance R1 may be replaced by a reactance foralternating current voltage con- This reactance may have a magnetic corein which the permeability increases with increasing current to obtainbetter regulation of the voltage at the terminals 5, 6 and on the load.

Figure 2 shows a. circuit somewhat similar to the circuit of Figure l.In the circuit of Figure 2, however, I provide transformers T and T1interposed as shown between the resistance R1 and the resistance Rv.These transformers permit adjustment of the voltages on the resistanceR1 and on the resistance Rv in order to obtain suitable relation betweenthe constants or values of the respective resistances or regulatingelements and the circuit toV be regulated.

In the circuit Of Figure 3 the resistance R1 is connectedto the primarywinding o1' a transformer Ta. The resistance Rv connects the otherterminal of this transformer winding to lead 2. One winding of thetransformer is connected as shown to the output terminal 5 so that anautotransformer effect is obtained which permitsl regulating theconstants of the circuit with respect to the load circuit which is toutilize the voltages from 5 and 6. 'Ihe autotransformer makes itpossible to obtain a circuit combination which completely suppressesvoltage variations to a constant impedance load when the line voltagevaries.

To simplify the description of my invention I have assumed that theresistance Rv is of the Thyrite type. However, my invention contemplatesthe use of any material or device to replace Rv provided said materialor device has the required ncn-linearity relation between the appliedvoltage and the resistance. For example Rv may be replaced by arectifying device of the oxide type. These rectiflers have current andresistance and voltage characteristics as indicated in Figure 4. Theelement Rv may also be replaced by photo cells or other cells which havethe required characteristics.

Having thus described my invention and the operation thereof, what Iclaim is: I

1. The voltage regulating circuit comprising, a pair of leads eachhaving a terminal which may be connected to a source of voltage whichmay vary, and another terminal which may be connected to a load circuit,an inductive reactance, a resistance the value of which increasesrapidly as the current therethrough increases connected in series withsaid reactance in one of said leads, a second inductive reactance and arectifier of the oxide type the current through which increases rapidlyas the voltage across the terminals thereof increases connected inseries with said second inductive reactance between said leads.

2. A voltage regulating circuit comprising, a pair of leads each havinga terminal which may be connected to a source of voltage whichv mayvary, and another terminal which may be connected to a load circuit, aresistance the value of which increases rapidly as the currenttherethrough increases connected in series with one of said leads, acesium oxide photo cell the current through which increases rapidly asthe voltage across the terminals thereof increases connected betweensaid leads, an inductance in series with said resistance, and aninductance in series with said cell.

3. A voltage regulating circuit comprising, a `pair of leads each havinga terminal which may be connected to a source of voltage which may vary,and another terminal lwhich may be connected to a load circuit, aninductive reactance, a resistance the value of which increases rapidlyas the current therethrough increases connected in series with saidinductive reactance in one of said leads, and an element the currentthrough which increases rapidly as the voltage across the terminalsthereof increases connected between the juncture between said resistanceand inductive reactance and the other of said leads.

4. A voltage regulating circuit comprising, a pair of leads each havinga terminal which may be connected to a. source of voltage which mayvary, and another terminal which may be connected to a load circuit, atransformer winding,

a resistance the value of which increases rapidly and continuously asthe current therethrough increases connected in series with said windingin Jone of said leads, a second transformer winding coupled to said rstnamed winding, and a second resistance the current through whichincreases rapidly and continuously as the voltage across the terminalsthereof increases connected in series with said second transformerwinding between said leads.

5. AA voltage regulating circuit comprising, a pair of leads each havinga terminal which may be connected to a source of voltage which may vary,a second terminal which may be connected to a load circuit, a resistancethe value of which increases rapidly as the current therethroughincreases, connected in series with one of said leads, an inductanceconnected in series with said resistance, a photo cell the currentthrough which increases rapidly as the voltage across the terminalsthereof increases connected between said leads and a second inductanceconnected in s eries with said photo cell to which said inductances arecoupled.

6. A voltage regulating circuit comprising, a pair of leads each havinga terminal which may be connected to a source of voltage which may vary,and another terminal which may be connected to a load circuit, aninductive reactance, a resistance the value of which increases rapidlyas the current therethrough increases connected in series with saidreactance in one of said leads, a second inductive reactance, and aresistance the value of which decreases rapidly as the voltage acrossthe terminals increases connected in series with said second inductivereactance.

7. A voltage regulating circuit comprising, a pair of leads each havinga terminal which may be connected to a source of voltage which may vary,and another terminal which may be connected to a load circuit, aresistance in series with one of the leads, the value of which increasesrapidly with increasing current, a first transformer winding connectedin series with the source of voltage, the resistance and the loadcircuit, a second transformer winding coupled to the first mentionedtransformer winding, said second transformer winding being connectedacross said pair of leads, one terminal being connected between thejunction points of the first mentioned transformer winding and saidresistance, said second transformer winding having in series therewith aresistance, the value of which decreases rapidly with increasingvoltage.

8. A voltage regulating circuit comprising, a pair of leads each havinga terminal which may be connected to a source of voltage which may vary,and another terminal which may be connected to a load circuit, atransformer having a primary winding in series with said pair of leads,said transformer having a secondary winding across which is connected aresistance the value of which increases rapidly with increasing voltage,a second transformer having a primary winding connected between saidpair of leads on the load side of said first mentioned transformer, saidsecond transformer having a secondary winding across which is connecteda resistance the value of which decreases rapidly with increasingvoltage.

CLARENCE W. HANSELL.

